Chassis interlock latch with auto-lock mechanism

Abstract

A latch assembly provides options for the retention within a rack of a chassis, and the retention within the chassis of a device. With the device in a device slot of the chassis, and the chassis installed in the rack, a first latch in a completely extended position prevents the device from being removed from the slot and prevents a latch tooth from being disengaged from the rack. With the first latch in an intermediate position, the latch tooth may be disengaged from the rack and the chassis removed from the rack, but the device may not be fully removed from the device slot. With the first latch in a retracted position the chassis may be removed from the rack and/or the device may be removed from the device slot.

What is claimed is: 
     
       1. An apparatus comprising a first latch including:
 a pin configured to move between an extended position and a retracted position, the pin including a shoulder; 
 a first spring biasing the pin toward the extended position; 
 a first slider movable between a first overlapping position and a first non-overlapping position with respect to the shoulder; 
 a second spring biasing the first slider toward the first overlapping position; 
 a second slider moveable between a triggering position and a non-triggering position with respect to the pin; 
 a third spring biasing the second slider toward the triggering position, wherein: 
 when the pin is in the retracted position and the second slider is in the non-triggering position, the second spring urges the first slider to the overlapping position in which the first slider prevents the pin from being moved to the extended position by the first spring; and 
 when the pin is in the retracted position with the first slider overlapping the shoulder, movement of the second slider to the triggering position moves the first slider from the overlapping position, which allows the pin to be moved by the first spring to abut the second slider at a first intermediate position between the retracted position and the extended position. 
 
     
     
       2. The apparatus of  claim 1 , wherein:
 the first slider has a first thickness and includes a first slot configured to receive the pin; 
 the second slider has a second thickness less than the first thickness and includes a second slot configured to receive the pin and a trigger extending through a window of the first latch; and 
 the first slider and the second slider work in opposition about the pin such that movement of the first slider toward the pin causes ends of the first slot to abut ends of the second slot, which causes the second slider to move away from the pin. 
 
     
     
       3. The apparatus of  claim 2 , wherein:
 the third spring is configured to be stronger than the second spring such that, absent an external force on the first slider and second slider and with the pin in the retracted position, the third spring overcomes the second spring and maintains the pin within the second slot, with the pin displaced from the first slot. 
 
     
     
       4. The apparatus of  claim 1 , wherein the first latch is incorporated into a first chassis, the apparatus further including:
 a second chassis including:
 a second latch provided with a latch tooth movable between a locked position and an unlocked position; 
 a fourth spring biasing the latch tooth toward the locked position; and 
 a device slot for receiving the first chassis, wherein: 
 
 when the first chassis is within the device slot, the latch tooth is in the locked position, and the pin is in the extended position, the pin hinders movement of the latch tooth toward the unlocked position. 
 
     
     
       5. The apparatus of  claim 4 , wherein latch tooth movement from the unlocked to the locked position is perpendicular to pin movement from the extended to the retracted position, and movements of the first slider and the second slider are perpendicular to both latch tooth movement from the unlocked to the locked position and pin movement from the extended to the retracted position. 
     
     
       6. The apparatus of  claim 4 , wherein:
 when the pin is in the retracted position, the first chassis may be inserted and removed from the device slot; and 
 when the first chassis is received within the device slot and the pin is in the extended position, the pin extends into the first chassis, preventing the first chassis from being removed from the device slot. 
 
     
     
       7. The apparatus of  claim 6 , wherein the second chassis includes:
 an elongate slot configured to admit the pin into the first chassis; and 
 a striker provided over a section of the elongate slot such that, when the first chassis is in a fully-received position within the device slot, the pin may extend through the elongate slot to the extended position, and, when the first chassis is in a partially-received position within the device slot, the pin may extend through the elongate slot to a second intermediate position abutting the striker. 
 
     
     
       8. The apparatus of  claim 7 , wherein:
 within the pin in the retracted position, the first chassis is moveable with respect to the device slot between the fully-received position, the partially-received position, and an extracted position; 
 when the second chassis is in the fully-received position, the pin is movable from the retracted position through the pin slot to the extended position; 
 when the second chassis is in the partially-received position, the pin is moveable between the retracted position through the pin slot to the second intermediate position; and 
 when the first chassis is in the partially-received position and the pin is at the second intermediate position:
 movement of the first chassis to the extracted position is hindered by the pin slot limiting pin travel, and 
 the latch tooth is moveable to the unlocked position without being hindered by the pin. 
 
 
     
     
       9. The apparatus of  claim 8 , wherein:
 when the first chassis is in the fully-received position or the partially-received position, the first chassis is biased toward the extracted position by a fifth spring; 
 when the first chassis is in the fully-received position and the pin is moved from the extended position toward the retracted position, as the pin passes the striker, the first chassis is moved to the partially-received position by the fifth spring, and further movement of the first chassis to the extended position is prevented by the pin abutting an edge of the elongated slot. 
 
     
     
       10. The apparatus of  claim 9 , wherein:
 the first slider has a first thickness and includes a first slot configured to receive the pin; 
 the second slider has a second thickness less than the first thickness and includes a second slot configured to receive the pin and a trigger extending through a window of the first latch; and 
 the first slider and the second slider work in opposition about the pin such that movement of the first slider toward the pin causes ends of the first slot to abut ends of the second slot, which causes the second slider to move away from the pin. 
 
     
     
       11. The apparatus of  claim 10 , the second chassis provided with a lip configured to abut the trigger, the lip moving the trigger back within the window as the first chassis is moved from the partially-inserted position to the fully-inserted position within the device slot, the movement of the trigger causing a corresponding movement of the second slot away from the pin such that, with the first chassis in the fully-inserted position, the trigger is moved back within the window and the pin is fully withdrawn from the second slot. 
     
     
       12. The apparatus of  claim 11 , wherein the second chassis is provided with a handle including a chamfer configured such that, when the first chassis is in the extracted position and the pin is in the extended position, as the first chassis is inserted into the device slot, the pin abuts the chamfer and with further insertion the pin is compressed by the chamfer toward the retracted position until the pin passes an end of the chamfer. 
     
     
       13. The apparatus of  claim 12 , wherein the lip is provided on the handle and configured such that, when the first chassis is in the extracted position and the pin is in the extended position, as the first chassis is inserted into the device slot, the pin moves along the chamfer and past the lip without abutting the lip. 
     
     
       14. The apparatus of  claim 1  further including a lever connected to the pin by which the pin is movable to the retracted position. 
     
     
       15. The apparatus of  claim 4  wherein the fourth spring is a leaf spring, the first, second, and third springs are coil springs, and a tab connected to the fourth spring may be actuated to move the latch tooth from the locked position to the unlocked position.